So basically this song is kind of controversial among rhythm guitarists. It sounds awesome to play, but most seemed very upset with the way GH handled it. I've never played that chart to be honest, so I can't make any fair comparisons. But I believe this is a pretty OK chart.
The main riff is pretty crazy, you've got a GRY GRO snake pattern that throws in a speedy BYRG scale in the respective order I listed. I found this riff to be pretty fun to play, as it takes a lot of technical skill to pull off correctly, and it really felt awesome.
The rest of the song is your basic rush style chord and alt strum verse, with the repeated intro riff during choruses.
The song slows down at the end, and gives you a cool plucky section, and then the guitar solo, which is easy compared to the intro. It's just a bunch of fast alt strum bursts with a quick snake at the end to round it up. The song plays out until the BRE.
Overall it's a fun song. Like I stated in the intro, it has plenty of challenge and takes lots of skill to play accurately, but once you get it down it's a blast. Is it impossible? Arguably, but I still get it if you a Rush fan.
And those wondering about the live version, it sounds like the one from GH5, so it's not a terrible live version. Not as good as the one from Exit...stage left, but it's decent and Geddy and everyone still played it with vigor and energy like they always do.